Robbin Harris Ceramics


Do you do custom work/commissions? 

Yes I do. Please contact me with any ideas, questions or custom desires. If I think I can do a good job and still enjoy the process I will reach out and discuss costs and timeline. 

What is crystalline and why is it so costly?

Crystalline is a specialist type of glaze where zinc silicate crystals form in the glaze during the kiln firing process. The glaze is mixed using a variety of raw materials, some measured in minute amounts.

Each piece is fired on a pedestal and dish to protect the kiln, as there is a lot of glaze run off during the firing. This needs to be removed after the firing, which is a delicate process, and the bottom of each piece ground smooth using a diamond disc.

Crystalline glaze typically has a high failure rate, which can be frustrating and expensive, however when it works the effects are stunning.

The firing process uses a complex schedule with several temperature ramps to create different crystal growth formations. The kiln is fired to maximum temperature of around 1300c (cone 10), and then cooled to specific holding temperatures to allow crystals to form in the glaze. The amount of time held at this temperature contributes to the size of the crystals. Crystals occur randomly in the glaze, making each piece unique.